Safe or not?

Hello

I just noticed that my pc is working a little bit slower than before. After "welcome" screen I have a few secs blackscreen and after this 3 secs I can see my deskop. Yesterday I updated my norton and scanned everything. Nothing after NPE scan and full scan. Today I tried once more and I had update like 130mb (30 updates) after another scan I found in my history many NCW submissions. Files like: mspaint.exe, actioncenter.dl, dwmcore.dll, colorui.dll and other. And looks like they are microsoft files. No update or anything so why I have microsoft files in norton history?